US8529189B2ActiveUtilityPatentIndex 86
Linear quadratic regulator control for bleed air system fan air valve
Est. expiryJan 30, 2029(~2.6 yrs left)· nominal 20-yr term from priority
F02C 6/08F05D 2270/303F02C 7/14Y02T50/60
86
PatentIndex Score
29
Cited by
19
References
17
Claims
Abstract
A system and method are provided for controlling the temperature of engine bleed air from a turbofan gas turbine engine. The system includes a fan air valve and a fan air valve controller. The fan air valve is adapted to receive a flow of fan air from a turbofan gas turbine engine intake fan. The fan air valve is coupled to receive valve position commands and is configured, in response to the valve position commands, to move to a valve position to thereby control the engine bleed air temperature. The fan air valve controller is configured to implement a linear quadratic regulator (LQR) control. The fan air valve controller is adapted to receive a plurality of sensor signals, each sensor signal representative of one or more system parameters, and is configured, in response to the sensor signals, to supply the valve position commands to the fan air valve.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A system for controlling gas turbine engine bleed air temperature, comprising:
a fan air valve adapted to receive a flow of fan air from a turbofan gas turbine engine intake fan, the fan air valve coupled to receive valve position commands and configured, in response to the valve position commands, to move to a valve position to thereby control the engine bleed air temperature; and
a fan air valve controller configured to implement a linear quadratic regulator (LQR) control, the fan air valve controller adapted to receive a plurality of sensor signals, each sensor signal representative of one or more system parameters, the controller configured, in response to the sensor signals, to supply the valve position commands to the fan air valve.
2. The system of claim 1 , wherein the system parameters include fan air temperature, fan air flow, and engine bleed air temperature.
3. The system of claim 2 , further comprising:
a heat exchanger having a bleed air inlet, a bleed air outlet, a fan air inlet, and a fan air outlet, the bleed air inlet adapted to receive a flow of bleed air from a turbofan gas turbine engine, the cooling air inlet adapted to receive a flow of fan air from a turbofan gas turbine engine intake fan, the heat exchanger configured to facilitate heat transfer from the bleed air to the fan air and thereby discharge relatively cooler bleed air from the bleed air outlet, and relatively warmer fan air from the fan air outlet.
4. They system of claim 3 , wherein the LQR control implements a state space model derived from a linear model of the system, the state space model defined by:
[
δ
T
.
S
δ
T
.
HX
δ
W
.
C
]
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
[
T
S
T
HX
W
C
]
+
[
0
0
K
V
τ
V
]
i
y
=
[
1
0
0
]
[
T
S
T
HX
W
C
]
+
0
i
wherein:
δ({dot over ( )}) represents rate of change of bleed air temperature (T S ), fan air temperature (T Hx ), and fan air flow through the heat exchanger (W C );
τ represent the applicable time constants, and K represent the gains of the sensed bleed air exit temperature (S), the heat exchanger (HX), and the valve (V); and
i represents fan air valve drive current.
5. The system of claim 4 , wherein the LQR control is configured to continuously determine a state estimation error and, based on the determined state estimation error, generate a new matrix (B) that includes fan air valve gain and fan air valve time constant, where:
B
=
[
0
0
K
V
τ
V
]
.
6. The system of claim 5 , wherein the state estimation error is calculated as follows:
E
=
[
A
B
C
D
]
-
1
[
0
⋮
1
]
,
and
e
=
E
(
n
)
+
K
*
E
(
1
:
n
)
.
7. The system of claim 5 , wherein the LQR control continuously generates a new system state matrix (A), where:
A
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
.
8. A turbofan gas turbine engine bleed air temperature control system, comprising:
a heat exchanger having a bleed air inlet, a bleed air outlet, a cooling air inlet, and a cooling air outlet, the bleed air inlet adapted to receive a flow of bleed air from a turbofan gas turbine engine, the cooling air inlet adapted to receive a flow of cooling air from a turbofan gas turbine engine intake fan, the heat exchanger configured to facilitate heat transfer from the bleed air to the cooling air and thereby discharge relatively cooler bleed air from the bleed air outlet, and relatively warmer cooling air from the cooling air outlet;
a bleed air temperature sensor disposed downstream of the bleed air outlet, the bleed air temperature sensor configured to sense the temperature of the bleed air discharged from the bleed air outlet and supply a bleed air temperature signal representative thereof;
a fan air temperature sensor disposed downstream of the fan air outlet, the fan air temperature sensor configured to sense the temperature of the fan air discharged from the fan air outlet and supply a fan air temperature signal representative thereof;
a fan air valve disposed upstream of the cooling air inlet, the fan air valve coupled to receive valve position commands and configured, in response to the valve position commands, to move to a valve position and thereby control the flow of cooling air into the cooling air inlet; and
a fan air valve controller configured to implement a linear quadratic regulator (LQR) control, the fan air valve controller adapted to receive at least the bleed air temperature signal, the fan air temperature signal, and a signal representative of fan air flow through the heat exchanger, and configured, in response to at least these signals, to supply the valve position commands to the fan air valve.
9. They system of claim 8 , wherein the LQR control implements a state space model derived from a linear model of the system, the state space model defined by:
[
δ
T
.
S
δ
T
.
HX
δ
W
.
C
]
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
[
T
S
T
HX
W
C
]
+
[
0
0
K
V
τ
V
]
i
y
=
[
1
0
0
]
[
T
S
T
HX
W
C
]
+
0
i
wherein:
δ({dot over ( )}) represents rate of change of bleed air temperature (T S ), fan air temperature (T Hx ), and fan air flow through the heat exchanger (W C );
τ represent the applicable time constants, and K represent the gains of the sensed bleed air exit temperature (S), the heat exchanger (HX), and the valve (V); and
i represents fan air valve drive current.
10. The system of claim 9 , wherein the LQR control is configured to continuously determine a state estimation error and, based on the determined state estimation error, generate a new matrix (B) that includes fan air valve gain and fan air valve time constant, where:
B
=
[
0
0
K
V
τ
V
]
.
11. The system of claim 9 , wherein the state estimation error is calculated as follows:
E
=
[
A
B
C
D
]
-
1
[
0
⋮
1
]
,
and
e
=
E
(
n
)
+
K
*
E
(
1
:
n
)
.
12. The system of claim 9 , wherein the LQR control continuously generates a new system state matrix (A), where:
A
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
.
13. A method of controlling bleed air temperature from a turbofan gas turbine engine, the method comprising the steps of:
flowing engine bleed air through a heat exchanger;
flowing fan air through a fan air valve and the heat exchanger to thereby cool the engine bleed air and supply cooled engine bleed air, the fan air valve disposed upstream of the heat exchanger;
determining cooled engine bleed air temperature;
determining fan air temperature;
determining fan air flow through the heat exchanger;
supplying the determined fan air flow, fan air temperature, and cooled engine bleed air temperature to a controller that implements linear quadratic regulator (LQR) control; and
using linear quadratic regulator (LQR) control to control fan air valve position, to thereby control fan air flow into the heat exchanger and cooled engine bleed air temperature.
14. They method of claim 13 , further comprising:
developing a linear model of a system that includes at least the fan air valve, the heat exchanger, and a cooled engine bleed air temperature sensor; and
deriving a state space model from the linear model of the system, the state space model defined by:
[
δ
T
.
S
δ
T
.
HX
δ
W
.
C
]
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
[
T
S
T
HX
W
C
]
+
[
0
0
K
V
τ
V
]
i
y
=
[
1
0
0
]
[
T
S
T
HX
W
C
]
+
0
i
wherein:
δ({dot over ( )}) represents rate of change of cooled engine bleed air temperature (T S ), fan air temperature (T Hx ), and fan air flow through the heat exchanger (W C );
τ represent the applicable time constants, and K represent the gains of sensed cooled bleed air temperature (S), the heat exchanger (HX), and the valve (V); and
i represents fan air valve drive current.
15. The method of claim 14 , further comprising:
continuously determining a state estimation error; and
based on the determined state estimation error, generating a new matrix (B) that includes fan air valve gain and fan air valve time constant, where:
B
=
[
0
0
K
V
τ
V
]
.
16. The method of claim 15 , wherein the state estimation error is continuously determined as follows:
E
=
[
A
B
C
D
]
-
1
[
0
⋮
1
]
,
and
e
=
E
(
n
)
+
K
*
E
(
1
:
n
)
.
17. The method of claim 15 , further comprising continuously generating a new system state matrix (A), where:
A
=
[
-
1
τ
S
1
τ
S
0
0
-
1
τ
HX
K
HX
τ
HX
0
0
-
1
τ
V
]
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